1st GoJelly Newsletter, 24. 12. 2018
Author: Jamileh Javidpour (Coordinator, SDU, Denmark)
One of the major causes global warming has, is an increase in both frequency and magnitude of jellyfish blooms, especially in temperate regions. Although jellyfish are among oldest multi-organ animals that survived over 500 million years of the earth history and belonging to a healthy marine ecosystem, they were seen in most parts of the world as pest because of their possible negative impacts on ecosystem goods and services by reducing harvested valuable fish stocks, thus limiting carbon and energy flow to higher trophic levels, clogging cooling water systems of power plants and causing detrimental economic impacts on aquaculture, tourism and coastal infrastructures.
However, in a different line of thinking, jellyfish were viewed as a potential target product and recently attempts were made to utilize jellyfish products even as part of “baby diapers” in nanotechnology or for pharmacy. Indeed, Japanese and Chinese have been eating jellyfish for more than a thousand years. To exchange obstacles with opportunities GoJelly aims to create a new paradigm shift transforming an existing marine debris problem into new solutions in which jellyfish serve as an anti-microplastic filter and raw material for a variety of blue-green biotechnology products. The present newsletter unveils the first results of GoJelly within WP2, 4 and 6 after the first year.
WP2: Analysing the role of jellyfish within the food web
Authors: Nicole Aberle-Malzahn (NTNU, Norway) and Jan Dierking (GEOMAR, Germany)
What do jellyfish eat? Which food items have the right quality to allow jellyfish to grow and proliferate? And who feeds on jellyfish? Answers to these questions are important when we want to understand the role of jellyfish in the sea, but also, to better understand when and where jellyfish blooms occur.
As part of GoJelly, we thus aim to analyse different marine food webs during jellyfish seasons in different case study areas including the Baltic Sea, Norwegian Sea, Eastern Mediterranean, Adriatic Sea and the North-East Atlantic off Madeira.
Over the course of 2018, our sampling in these locations has started and is getting in full swing. Following a specific protocol, the GoJelly teams from Germany, Norway, Israel and Slovenia have added comprehensive sampling campaigns for food-web analyses to their regular jellyfish harvesting. On board of research vessels, the teams deployed specific water samplers to obtain seawater samples from the water column and used filtration units to collect the organic matter on filters and to analyse nutrient and chlorophyll concentrations of the seawater. Plankton nets were deployed to account for the different prey items that could support jellyfish growth. Finally, bycatch e.g. from trawling activities for jellyfish harvesting was documented and samples for food-web analysis (ranging from crustaceans to fish) were taken.
Laboratory analyses at GEOMAR Kiel and University of Hamburg are now the focus to reconstruct jellyfish food webs and diet in the different locations. The methods we use to do so are called stable isotope and fatty acid analysis, two modern methods that allow us to use the chemical composition of our samples to determine who has been feeding on who and how nutritious different food items are.
The food-web data obtained will complement the GoJelly databank which comprises currently published data-sets from more than 200 published articles dealing with a variety of different aspects that are considered as relevant to promote jellyfish bloom formation – and will hopefully bring us one step closer to predicting when and where exactly jellyfish blooms will form.
WP2: Modelling activities
Author: Lionel Eisenhauer (SINTEF, Norway)
The modelling activity for the simulation and prediction of jellyfish blooms during year 1 was primarily focused on the development of an entirely new nested model domain for the Mediterranean and Adriatic Seas at respectively 4 km and 800 m horizontal resolution, including the data on the bathymetric profile, year specific riverine input data, atmospheric forcing parameters, hydrographic parameters and the preliminary assessment of the simulated general circulation pattern reproducing the major features such as the Po plume front and the main gyres over the South Adriatic Pit. Therefore, hindcast simulations have been run for recent past years from 2012-2017.
The SINMOD ecosystem model has been further extended by including a first model for the temperature dependent strobilation response of scyphistomae stages for the meroplanktonic scyphozoan model species A. aurita. The response has been tested in a 1D-water column setup of the SINMOD ecosystem model at a site in the northern part of the Adriatic Sea known to host benthic A. aurita populations. The model was forced by the hydrographic conditions provided by the 3D-model setup, i.e. temperature and vertical mixing. The modelled strobilation response was simulated for 2 different years under realistic seasonal temperature patterns. The simulated strobilation initiation occurred in November, matching the general seasonal pattern for the Northern Adriatic Sea ecosystem.
WP4 and 6: Lessons we learned from the fertilizer experiment
Author: Thorsten Reinsch (CAU, Germany)
We investigated in some small-scale experiments the influence of jellyfish species- as promoter- on seed germination and soil water holding capacity. The results showed some positive effects, however, germination was heavily dependent on the amount of jellyfish as at high application rates plant growth can be depressed due to high salt concentration or other adverse compounds. Thus, we also observed that pre-processing methods of JF raw material has an important effect of the germination rates. Moreover, the concentration of main plant nutrients in JF was largely different in each species. Having a closer look on species gathered from the Baltic and Northern See region such as Aurelia and Cyania, elements like nitrogen (N) and phosphorus (P) are considerable higher (7-fold) in Cyania species. However, the total concentration is still below commercial fertilizers. Nevertheless, because of other trace elements (e.g. Ca and Mg) applied together with N and P, JF based fertilizer might be interesting as a complex fertilizer, when high plant uptake rates can be achieved.
In the first year of the project a lot of time was spend in literature review, collecting JF biomass from different areas and establishment of different post-treatment procedures to conserve JF as dried material without losing plant nutrient compounds. With regard to preliminary results, we will establish a sequence of systematically experiments: i) the effect of JF on soil microbial activity, ii) on plant growth iii) and as pesticide. The hierarchical structure (soil activity – biomass yield – plant health) of the sequence is necessary to fully understand the processes in which JF as a fertilizer might be involved rather than just to monitor the effect on plant growth. The experiment i) will start in the beginning of January and includes the measurements of soil water retention, soil respiration, nitrous oxide emissions and soil microbial communities.
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 774499”